Thermal detectors, also referred to as infrared (IR) detectors, are sensors that operate by absorbing energy from electromagnetic radiation and by converting the heat generated by the absorption of this energy into an electrical signal representative of the amount of absorbed radiation. Thermal detectors may be utilized to detect fires, overheating machinery, planes, vehicles, people, animals, and any other objects that emit thermal radiation. Thermal detectors may also be used in non-imaging applications such as radiometers, gas detectors, and other thermal or infrared detectors.
On type of thermal detector is known as a microbolometer detector. A microbolometer detector is generally based on a suspended platform structure, sometimes referred to as a bridge. The platform structure is generally held above and thermally insulated from a substrate by a support structure. The suspended platform structure may be provided with a thermistor whose electrical resistivity varies in response to temperature variations caused by the absorbed radiation.